Expressions of aquaporin 1-3 in normal and hydronephrotic fetal kidneys

Abstract

Objective To explore the differential expressions of aquaporin 1-3 in normal and hydronephrotic fetal kidney. Methods Thirty cases of aborted fetal kidneys were collected from healthy mothers and diagnosed as normal or hydronephrosis by urinary ultrasound. Among them, 21 were normal (second trimester, n=12; third trimester, n=9) while the remainder belonged to hydronephrosis (third trimester, n=9). Meanwhile, 8 cases of adult normal kidney tissues adjacent to carcinoma were collected as positive controls. Immunohistochemistry and Western bolt were used for examining the locations and expressions of aquaporin 1-3 in kidney. Results Immunohistochemistry showed that AQP1-positive staining was predominantly distributed in glomerular capillary endothelial cells, proximal convoluted tubule epithelial cells and epithelial cells of descending thin myelin loops; AQP2-positive staining was predominantly located in renal collecting duct epithelial cell membrane and cytoplasm; AQP3-positive staining was predominantly distributed in basal principal cells of renal collecting duct. Analysis of Image-Pro plus software showed that renal AQP1-3 expressions in second trimesters were weaker than those in third trimesters (0.375±0.056 vs 0.483±0.062, 0.278±0.031 vs 0.356±0.048, 0.312±0.050 vs 0.501±0.068) and the expressions in hydronephrotic kidney were (0.308±0.051, 0.247±0.039 & 0.282±0.056) lower than those in normal kidney of the same trimesters. And the above results were confirmed by Western blot. The expressions of AQP1-3 in second and third trimesters and hydronephrotic fetus kidney were 0.82±0.05 vs 0.96±0.07 vs 0.54±0.04, 0.76±0.04 vs 0.94±0.06 vs 0.42±0.03 and 0.79±0.04 vs 0.95±0.05 vs 0.53±0.04 respectively. Conclusions The expressions of AQP1-3 in fetal kidney increase with gestational age. And a lower expression of AQP1-3 implies that renal function has changed in fetal hydronephrotic kidney. Key words: Aquaporin; Fetus; Hydronephrosis